Jointer "Toothed table lips for noise reduction"?

[Jamie Buxton]

In another thread, Timo Christ provides a link to a Bernardo jointer/planer available in Europe. One part of the spec caught my eye. It says "Toothed table lips for noise reduction." Noise reduction would be a good thing on my Hammer jointer/planer. It is tolerably noisy when it is running by itself, but when the chip collector is running with it, the noise is a howl. It sounds like a siren. I'm sure the issue is that the chip collector is sucking air past the rotating knife head, and the changing aperture through the jointer tables is causing the howl. I've always just bought the best earmuffs I can find. But maybe this toothing approach would give some benefit.

Has anybody ever seen a jointer table treated in this way?

Has anybody ever tried grinding teeth into the table lips to see if it helps?

[Jim Becker]

My MiniMax FS-350 J/P has "toothed" transitions between the tables and the cutter head. It's still loud, although largely from the way the DC hood transitions from a very skinny wide slot to a 120mm round connection...the rushing air really gooses the noise level of the machine! (It's the one tool I never fail to wear hearing protection with...)

[lou sansone]

my direct drive 16" newman is not toothed and not all that loud. Maybe some of the noise on these machines is due to the fact that many are belt drive and spin faster than the direct drive machines. just a thought

lou

[Todd Burch]

I have a buddy that has a 12" SCMI and it is toothed. It's a reasonably quiet machine.

Todd

[Jamie Buxton]

Jim, this noise is not a big whoosh like air changing direction. It is a howl. The howl is much louder than either the jointer or the chip collector running separately.

Lou, I dunno about the speed issue. My machine specs say it runs at 5000 rpm with 50 Hz current (Hammer didn't supply an American spec). Maybe they changed the pulleys when they changed the motor for America, so maybe it still runs at 5000 rpm.

Now that I'm thinking about this, my howl exists only in the jointer configuration. The planer configuration of course uses the same hood and the same direction changes in the airstream. This points again to the tight slots around the jointer table lips. Maybe what I should try is to find some way to reduce the airflow past the jointer head -- a bleed duct or something. I bet I don't really need lots of airflow in the jointer mode; all the chips want to fall down into the duct anyhow. The configuration where I need lots of airflow is the planer mode. There the chips must get sucked up against gravity.

[John Renzetti]

hi Jamie, The earlier Hammer models (I think yours is about 4 yrs old) ran 20% faster because they were designed for 50hz. At 50hz the machine is relatively quiet. (I had an AF22 dust collector in 1998 that was the same. At 50hz it was very quiet. At 60hz it sounded like an F14. They redesigned the fan the next year and the AF22 became quiet again. )
Later they changed the pulleys so that the machine ran at the lower speed at 60hz. Changing the pulley might be your best bet. You could also try to alter the air flow by raising the planer bed slightly. See if this works.
take care,
John

[Timo Christ]

Hi All,
the toothed table lips definitely help. My cousin has a 24" J/P without toothed tables and it also howls. Seriously. He had a toothed 16" before which was much quieter, and he is certain that toothed tables help.
Higher speed should give better surface quality, so i'm reserved about slowing it down.
Regards,
Timo

[Paul Canaris]

My SAC is toothed, and is subjectively fairly quite with or without the DC running.

[Mike Wilkins]

Hey Timo. What kind of J/P does your cousin have. You stated a 24" machine which is a lot of machine. I know Laguna had a Hoffman J/P advertised in one of their catalogs in either a 20" or 24" size. I'll bet they cost a pretty penny!!

[Jamie Buxton]

.... The earlier Hammer models (I think yours is about 4 yrs old) ran 20% faster because they were designed for 50hz. ...

John, the sticker on mine says it was manufacturered in 1999. Does that make it a collectable first edition or something? :)

[Timo Christ]

Mike,
i'm not sure of the brand, it is a professional unit, about 25 years old. Made by a smaller german company. All cast iron, about 1 ton in weight. It looks similar to the Bäuerle units.
Most new j/p machines only go to 20", above it's dedicated jointer or planer.
24" is great, you can put wide glued up panels right through without follow-up work.

[Jamie Buxton]

The cause of my howl turned out to be tight Austrian design plus bigger-is-better American implementation. The Felder engineers built the internal chip collection hood so that it practically form-fits the jointer head. This undoubtedly provides good chip collection with a small chip collector. However, in my shop the jointer/planer is connected by about 10' of 6" duct to a big cyclone. The cyclone was probably trying to suck 800-900 cfm through the gaps around the knife head. The fix turned out to be to cut some holes in the hood, so that only some of the air is coming through the knife-head gaps. I set the size of the holes so that I get a little howling, but not too much. My neighbors are much happier.

In this age of bigger and bigger chip collectors, who'd a thunk that bigger isn't necessarily better?

[lou sansone]

wow ... very interesting on the dust collection issue. thanks for the followup.

lou